Patent GB-191416316-A (GB)
Title: Telephone Installations in which the Subscribers' Lines are Grouped according to the Frequency of the Calls.
Filed: 1914-07-08
Granted: 1915-08-12
Abstract: 16,316. Siemens & Halske Akt.-Ges. Sept. 25, 1913, [Convention date]. [Addition to 28,751/12.] Automatic and semi-automatic exchange systems.-Relates to a system of the kind described in the parent Specification, in which the subscribers are divided into two classes, the subscribers of the first class, comprising those who call most frequently, being provided with impulse-transmitters for setting up their own connexions, while the connexions of subscribers of the second class are set up by means of the impulse-transmitters of exchange operators, who are automatically connected by service selectors to the calling circuits. The present invention provides a system of this sort in which the setting in action of a service selector DW, when a call comes from a subscriber W of the second class, is effected at a repeater Ue located between the calling line and the first group selector IGW. The operations will be described first for a call by a subscriber V of the first class and then for a call from a subscriber W of the second class. Full-automatic connexion. When the calling subscriber V has been connected by first and second preliminary selectors IVW, IIVW to the relay repeater set Ue associated with the first group selector IGW, relays A, B, C, V1, Fig. 1, and C1, C2, B1, Fig. 2, are energized. The relays C, C2 lock themselves independently of their first circuits. Each set of line interruptions transmitted by the subscriber's sender is repeated by the relay A to the line wire a at the contact 114, and while each set is being transmitted, the relay V2 is energized and connects battery to the line wire b at the contact 118. The first set of impulses in the wire a operates the relay A1 and vertical magnet H to raise the selector IGW. At the .first step the opening of the normal contact k1 deenergizes the relay C1, which opens the original energizing-circuit of the relay B1, but as long as the impulses are passing the relay B1 is kept energized by a circuit through its third winding and the wire b. At the conclusion of the first set of impulses, the wire b is disconnected from battery at the contact 118, and the relay B, de-energizes and completes the circuit of the rotary magnet D. When the selector finds an idle line in the selected level, the relay B1 is again energized by a circuit through its third winding and the outgoing test wire c<1>, and disconnects the rotary magnet D. At the first rotary step the contact 107 was opened and 107<1> closed, so that the relay B, now locks itself to the incoming test wire c and unlocks the relay C2. The de-energization of the relay C2 prepares the circuit of the release magnet M and connects the outgoing test wire c<1> to the release relay MR, which opens the release circuit at the contact 145. The second and further sets of impulses are transmitted to further selectors which are not shown. Semi-automatic connexion; selection of operator's circuits. When a calling subscriber W of the non-automatic class is connected by first and second preliminary selectors IVW<1>, IIVW<1> to the repeater Ue, a relay DC is energized, which was not energized in the case of the automatic subscriber V. This differential effect is secured by providing a battery connexion to the fourth wipers of the preliminary selectors IIVW<1> accessible to the non - automatic subscribers, while this connexion is not provided in the corresponding switches IIVW accessible to the automatic subscribers. The same difference may be made between the first preliminary selectors IVW, IVW<1>, in which case all the second preliminary selectors might be available to both classes of subscriber. The energization of the relay DC closes a contact 133 in the circuit of the rotary magnet D, of the service selector DW, while at the same time it disconnects the lateral circuits of the line a, b at the contacts 132, 119. When the selector DW finds an idle operator's circuit, the relay T1 is energized and open-circuits the rotary magnet D1, at the same time locking itself independently of the contact 143 of the relay DC. When the operator has inquired the wanted number, she writes it down on her key set, which controls the selectors IGW, &c., over the lines a, b. The taking into use of the operator's key set energizes a relay T2 which disconnects the calling line and locks the relays T1, DC so that these relays remain energized in spite of the de-energization of the relay C1 when the selector IGW is operated. When all the impulses have been sent, the relay T2 is de-energized and unlocks the relays DC, T1, so that the operator is disconnected. Release. When the calling subscriber hangs up his receiver, the relays A, B, V1 are deenergized and a circuit is comnleted for a relay S, which short-circuits the relay C. The relay C is thus unlocked and opens the incoming test circuit from the preliminary selectors, which are rendered available for further service by the unlocking of their test relays. The de-energization of the relay C also unlocks the relay B1, which completes the circuit of the selector release magnet M at the contact 127. If the called subscriber should be the first to hang up his receiver, the relay MR in the outgoing test circuit c' is de-energized and completes the release circuit at the contact 145, but the preliminary selectors are not released until the calling subscriber disconnects himself.